CN114402516B - Apparatus and method for controlling a delta-connected cascaded multilevel converter - Google Patents
Apparatus and method for controlling a delta-connected cascaded multilevel converter Download PDFInfo
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- CN114402516B CN114402516B CN202080064922.2A CN202080064922A CN114402516B CN 114402516 B CN114402516 B CN 114402516B CN 202080064922 A CN202080064922 A CN 202080064922A CN 114402516 B CN114402516 B CN 114402516B
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- 230000004048 modification Effects 0.000 description 7
- 238000012986 modification Methods 0.000 description 7
- 238000004364 calculation method Methods 0.000 description 6
- 238000012423 maintenance Methods 0.000 description 5
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
- H02M7/49—Combination of the output voltage waveforms of a plurality of converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0025—Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from ac input or output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
- H02M1/15—Arrangements for reducing ripples from dc input or output using active elements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/01—Arrangements for reducing harmonics or ripples
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
- H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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Abstract
An apparatus and method for controlling a delta-connected cascaded multilevel converter, the apparatus (100) for controlling a delta-connected cascaded multilevel converter (110) comprising: the converter controller (102) is configured to: receiving a current signal indicative of a phase current flowing through a respective phase leg of the converter (110); determining from the current signal a harmonic current signal indicative of the circulating current of the converter (110); and generating a harmonic voltage signal based on the determined harmonic current signal and the reference current signal such that the magnitude of the circulating current flowing through the phase leg of the inverter (110) is a predetermined magnitude.
Description
Technical Field
Embodiments of the present disclosure relate generally to the field of cascaded multilevel converters, and in particular, to an apparatus and method for controlling a delta-connected cascaded multilevel converter.
Background
Cascaded multilevel converters are promising candidates for drive and distribution system solutions. Cascaded multilevel converters can be easily operated at medium and high voltages based on series connected power modules or cells. Delta-connected cascaded multilevel converters have been advantageously applied to control power load imbalance. However, a disadvantage of delta-connected cascaded multilevel converters is that there is a circulating current through the three-phase arms. The circulating current may cause problems such as reduced efficiency of the converter.
To solve this problem, there are two alternative solutions. Some converter topologies, such as those of Y-connected cascaded multilevel converters, may naturally limit the circulating current through the three-phase legs, as there are no circuit paths for the circulating current in these converter topologies. However, at the same voltage level and power scale, the current rating of each converter cell in the Y-connected cascaded multilevel converter is much greater than the current rating of the delta-connected cascaded multilevel converter. To avoid parallel operation of the semiconductor devices, it may be recommended to use the topology of a delta-connected cascaded multilevel converter for large scale power applications.
For the topology of a delta-connected cascaded multilevel converter, some conventional solutions have been proposed to limit the circulating current. However, the control methods in the conventional solutions are all directed to static synchronous compensators (STATCOM) and cannot be directly applied to voltage driving.
It is desirable to provide an improved solution for controlling the circulating current of a delta-connected cascaded multilevel converter in voltage driven applications.
Disclosure of Invention
The disclosed embodiments are directed to an apparatus and method for controlling a delta-connected cascaded multilevel converter that is capable of increasing power capacity in a voltage driver.
In a first aspect, embodiments of the present disclosure provide an apparatus for controlling a delta-connected cascaded multilevel converter. The apparatus includes a converter controller configured to: receiving a current signal indicative of a phase current flowing through a respective phase leg of the converter; determining a harmonic current signal indicative of the circulating current of the converter from the current signal; and generating a harmonic voltage signal based on the determined harmonic current signal and the reference current signal such that the amplitude of the circulating current flowing through the phase leg of the converter is a predetermined amplitude.
The apparatus according to embodiments of the present disclosure controls injection of a circulating current having a desired magnitude into the phase leg with little or no modification to the hardware system of the converter as compared to conventional solutions to extend the rated power range of the converter. In this way, the power range is extended with minimal material costs for the converter.
In some embodiments, the converter controller is configured to: determining a harmonic current signal from the current signal indicative of a third harmonic circulating current of the converter; and generating the harmonic voltage signal such that the amplitude of the third-order harmonic circulating current is 0.167 times the rated current amplitude of the converter.
In some embodiments, the converter controller is further configured to: receiving a phase voltage reference signal associated with a load electrically coupled to the converter; and generating a control signal for controlling the converter by combining the harmonic voltage signal with the phase voltage reference signal such that the peak amplitude of the phase current is a first amplitude, wherein the first amplitude is associated with a second amplitude of the circulating current in the phase current.
In some embodiments, the converter controller is configured to generate the harmonic voltage signal based on a comparison of the harmonic current signal and the reference current signal.
In some embodiments, the converter controller is configured to: determining a first DC component of the harmonic current signal from the current signal; comparing the first DC component with a first reference DC component of a reference current signal to generate a first DC difference; determining a second DC component of the harmonic current signal from the current signal; comparing the second DC component to a second reference DC component of the reference current signal to generate a second DC difference; and generating a harmonic voltage signal based on the first DC difference and the second DC difference.
In some embodiments, the first reference DC component of the reference current is set to 0.167 times the nominal current amplitude of the converter and the second reference DC component of the reference current is set to zero.
In some embodiments, the converter controller is configured to: determining a first AC component of the harmonic current signal from the current signal; comparing the first AC component with a first reference AC component of the reference current signal to generate a first AC difference; determining a second AC component of the harmonic current signal from the current signal; comparing the second AC component with a second reference AC component of the reference current signal to generate a second AC difference; and generating a harmonic voltage signal based on the first AC difference and the second AC difference.
In some embodiments, the apparatus further comprises: and a unit controller configured to control one of the plurality of inverter units in the phase arm such that the amplitude of the circulating current is a predetermined amplitude, based on a unit control signal generated from the control signal.
In some embodiments, the unit controller is further configured to: receiving a DC voltage value indicative of a DC voltage across a capacitor of one of the plurality of converter cells; comparing the DC voltage value with a nominal value to generate a compensation factor; and controlling one of the plurality of converter cells based on the generated compensation factor and the cell control signal.
In some embodiments, the unit controller is configured to generate the compensation factor by dividing the DC voltage value by the nominal value.
In some embodiments, the unit controller is configured to: determining a compensation control signal by dividing a level of the unit control signal by a compensation factor; and controlling one of the plurality of converter units based on the compensation control signal.
In a second aspect, embodiments of the present disclosure provide a method for controlling a delta-connected cascaded multilevel converter. The method comprises the following steps: receiving a current signal indicative of a phase current flowing through a respective phase leg of the converter; determining a harmonic current signal indicative of the circulating current of the converter from the current signal; and generating a harmonic voltage signal based on the determined harmonic current signal and the reference current signal such that the amplitude of the circulating current flowing through the phase leg of the converter is a predetermined amplitude.
In some embodiments, determining the harmonic current signal indicative of the circulating current includes determining a harmonic current signal indicative of a third order harmonic circulating current, and generating the harmonic voltage signal such that the magnitude of the circulating current is a predetermined magnitude includes generating the harmonic voltage signal such that the magnitude of the third order harmonic circulating current is 0.167 times the nominal current magnitude of the converter.
In some embodiments, the method further comprises: receiving a phase voltage reference signal associated with a load electrically coupled to the converter; and generating a control signal for controlling the converter by combining the harmonic voltage signal with the phase voltage reference signal such that the peak amplitude of the phase current is a first amplitude, wherein the first amplitude is associated with a second amplitude of the circulating current in the phase current.
In some embodiments, generating the harmonic voltage signal includes generating the harmonic voltage signal based on a comparison of the harmonic current signal and a reference current signal.
In some embodiments, generating the harmonic voltage signal based on the comparison includes: determining a first DC component of the harmonic current signal from the current signal; comparing the first DC component with a first reference DC component of a reference current signal to generate a first DC difference; determining a second DC component of the harmonic current signal from the current signal; comparing the second DC component to a second reference DC component of the reference current signal to generate a second DC difference; and generating a harmonic voltage signal based on the first DC difference and the second DC difference.
In some embodiments, comparing the first DC component to the first reference DC component includes comparing the first DC component to 0.167 times the converter rated current amplitude, and wherein comparing the second DC component to the second reference DC component includes comparing the second DC component to zero.
In some embodiments, generating the harmonic voltage signal based on the comparison includes: determining a first AC component of the harmonic current signal from the current signal; comparing the first AC component with a first reference AC component of the reference current signal to generate a first AC difference; determining a second AC component of the harmonic current signal from the current signal; comparing the second AC component with a second reference AC component of the reference current signal to generate a second AC difference; and generating a harmonic voltage signal based on the first AC difference and the second AC difference.
In some embodiments, the method further comprises: one of the plurality of inverter units in the phase leg is controlled so that the amplitude of the circulating current is a predetermined amplitude based on a unit control signal generated from the control signal.
In some embodiments, the method further comprises: receiving a DC voltage value indicative of a DC voltage across a capacitor in one of the plurality of converter cells; comparing the DC voltage value with a nominal value to generate a compensation factor; and controlling one of the plurality of converter cells based on the generated compensation factor and the cell control signal.
In some embodiments, generating the compensation factor includes generating the compensation factor by dividing the DC voltage value by the nominal value.
In some embodiments, controlling one of the plurality of converter units comprises: determining a compensation control signal by dividing a level of the unit control signal by a compensation factor; and controlling one of the plurality of converter units based on the compensation control signal.
In a third aspect, the disclosed embodiments provide a system for controlling a delta-connected cascaded multilevel converter. The system comprises: an apparatus as described above; a first controller configured to generate a phase voltage reference signal based on a load electrically coupled to the inverter; and a second controller configured to generate a plurality of cell control signals for the plurality of converter cells based on the harmonic voltage signal.
In a fourth aspect, embodiments of the present disclosure provide a computer-readable medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method as described above.
According to an embodiment of the present disclosure, a circulating current of a delta-connected cascaded multilevel converter is controlled to have a desired amplitude and is injected into a phase arm. In this way, the power capacity of the delta-connected cascaded multilevel converter is improved with little or no modification to the hardware system, and the voltage ripple of the DC capacitors in each converter cell is reduced, thereby extending the operational life of the DC capacitors. In this way, the manufacturing cost of the delta-connected cascaded multilevel converter can be saved, the lifetime of the DC capacitor can be prolonged, and the maintenance cost of the DC capacitor can be reduced.
Drawings
The embodiments are shown and described with reference to the drawings. The drawings are intended to illustrate the basic principles and thus only illustrate aspects necessary to understand the basic principles. The figures are not drawn to scale. For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
fig. 1 shows a block diagram of an apparatus for controlling a delta-connected cascaded multilevel converter according to an embodiment of the disclosure;
FIG. 2 shows a circuit diagram of a delta-connected cascaded multilevel converter;
fig. 3 shows a circuit diagram of a converter cell of a delta-connected cascaded multilevel converter;
FIG. 4 shows a graph of third order harmonic circulating current for a delta-connected cascaded multilevel converter;
FIG. 5 illustrates a block diagram of a system for controlling a delta-connected cascaded multi-level converter in accordance with an embodiment of the present disclosure;
fig. 6 shows a block diagram of an apparatus for controlling the circulating current of a delta-connected cascaded multilevel converter according to an embodiment of the disclosure;
FIG. 7 illustrates a block diagram of a converter controller according to an embodiment of the disclosure;
FIG. 8 illustrates a graph of simulation results with and without a converter controller according to an embodiment of the disclosure;
FIG. 9 illustrates a graph of simulation results of closed loop control feedback of a converter controller in accordance with an embodiment of the disclosure; and is also provided with
Fig. 10 illustrates a flowchart of a method for controlling the circulating current of a delta-connected cascaded multilevel converter according to an embodiment of the present disclosure.
Detailed Description
The subject matter described herein will now be discussed with reference to several example embodiments. These embodiments are discussed only in order to enable those skilled in the art to better understand and thereby practice the subject matter of the present invention, and are not meant to imply any limitation on the scope of the subject matter.
The terms "comprising" or "including" and variations thereof are to be construed as open-ended terms, meaning "including, but not limited to. The term "or" should be read as "and/or" unless the context clearly indicates otherwise. The term "based on" is to be understood as "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Furthermore, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings. In the following description, the same reference numerals and signs are used to describe the same, similar or corresponding parts in the drawings. Other explicit and implicit definitions may be included below.
In the above conventional solutions, a method for controlling the circulating current in a STATCOM has been proposed for operating the STATCOM in an unbalanced voltage state. While conventional solutions utilize a delta-connected converter topology, not every converter cell has an AC source and rectifier circuit. Thus, this topology can only be used for STATCOM, and cannot be directly applied to voltage driving such as intermediate voltage (MV) driving. Injection of circulating current for power capacity expansion is not mentioned in conventional solutions. STATCOM only considers reactive power generation, whereas MV drive applications need to consider both active and reactive power generation. This means that for the same voltage range and power scale, the voltage ripple of the DC capacitor for MV drive applications is larger than for STATCOM applications. Thus, the circulating current control of a delta-connected cascaded multilevel converter for MV drive applications is more complex.
In view of the foregoing, the presently disclosed embodiments provide an improved solution for controlling the circulating current of a delta-connected cascaded multilevel converter that can be applied to voltage driving with little or no modification to its hardware system and that helps to improve the power capacity of the cascaded multilevel converter.
According to some embodiments, the circulating current is controlled by the converter controller to have a desired amplitude and is injected into the phase legs of the delta-connected cascaded multilevel converter. The converter controller determines a circulating current through the phase legs of the delta-connected cascaded multilevel converter and controls the circulating current in a closed loop manner such that the circulating current through the phase legs of the delta-connected cascaded multilevel converter is controlled to have a desired magnitude. In this way, a circulating current having a desired amplitude is injected into the phase leg to obtain the desired phase current, thereby extending the rated power range of the delta-connected cascaded multilevel converter.
Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.
Fig. 1 shows a block diagram of an apparatus 100 for controlling a delta-connected cascaded multi-level converter 110. The apparatus 100 includes a converter controller 102.
The inverter controller 102 is configured to receive current signals indicative of phase currents flowing through respective phase legs of the inverter 110. In some embodiments, the transducer 110 includes three phase arms connected to each other in a triangular shape. In some embodiments, the converter controller 102 receives current signals from the current sensors, respectively. The current sensor is electrically coupled to the phase arm and senses the phase current to generate a current signal representative of the phase current. In some embodiments, the current sensor may be included in the converter controller 102. In other embodiments, the current sensor may be disposed external to the inverter controller 102.
Further, the converter controller 102 is configured to determine a harmonic current signal from the current signal indicative of the 110-cycle current of the converter. The circulating current flows in the inverter 110 in a clockwise direction or a counterclockwise direction. The inverter controller 102 calculates a harmonic current signal from the received current signal representing the actual phase current of the corresponding phase leg. In some embodiments, the converter controller 102 may determine a harmonic current signal from the current signal that is indicative of a third order harmonic circulating current of the converter 110. In other embodiments, the converter controller 102 may determine a harmonic current signal indicative of any order harmonic circulating current.
Further, the converter controller 102 is configured to generate a harmonic voltage signal based on the determined harmonic current signal and the reference current signal. The harmonic voltage signal causes the magnitude of the circulating current flowing through the phase leg of the converter to be less than a predetermined magnitude. In some embodiments, the magnitude of the circulating current may be controlled to a predefined magnitude. In other embodiments, the magnitude of the circulating current may be controlled to zero. In some embodiments, the converter controller 102 generates the harmonic voltage signal such that the amplitude of the third order harmonic circulating current is a predetermined amplitude. In other embodiments, the converter controller 102 generates the harmonic voltage signal such that the amplitude of the harmonic circulating current of any order is a predetermined amplitude.
In some embodiments, the converter controller 102 generates the harmonic voltage signal based on a comparison of the harmonic current signal and the reference current signal. In some embodiments, the converter controller 102 compares the DC component of the harmonic current signal with the DC component of the reference current signal. In other embodiments, the converter controller 102 compares the AC component of the harmonic current signal with the AC component of the reference current signal.
According to some embodiments, the converter controller 102 generates harmonic voltage signals to control the circulating current in a closed-loop manner. Under such control, the circulating current flowing in the phase legs of the converter 110 may be controlled at a predefined amplitude. In some embodiments, the amplitude of the third harmonic circulating current is controlled to be 0.167 times the rated current amplitude of the converter 110. If the rated current of the inverter 110 is set to 1pu, the amplitude of the third harmonic circulating current is maintained at 0.167pu.
In some embodiments, the converter controller 102 is further configured to receive a phase voltage reference signal associated with a load electrically coupled to the converter 110. The phase voltage reference signal is generated for controlling the converter cells in the phase legs of the converter 110 to generate an output current set to meet the load demand.
In some embodiments, the converter controller 102 is further configured to generate the control signal by combining the harmonic voltage signal with the phase voltage reference signal. The control signal is used to control the inverter 110 such that the peak amplitude of the phase current is the first amplitude. The converter controller 102 may include a combiner or adder for combining the harmonic voltage signal with the phase voltage reference signal. The first amplitude is associated with a second amplitude of the circulating current in the phase current. In this way, a control signal for controlling the inverter unit of the inverter 110 is generated such that a phase current of a phase arm injected with a circulating current of a desired magnitude flows in the inverter 110.
In some embodiments, the peak value of the phase current or combined phase current reaches 0.866pu when a third harmonic circulating current of magnitude 0.167pu is injected into the phase arm. Thus, 1/0.866≡1.155 means that injecting a third order harmonic circulating current can help the converter 110 to obtain about 15.5% additional power. In this way, the rated power range of the converter 110 is expanded, and the power capacity of the converter 110 is increased. Further, due to the reduced peak value of the combined phase current, the voltage ripple of the DC capacitor in each converter cell in the phase leg of the converter 110 is reduced.
In some embodiments, the apparatus 100 may further comprise a converter unit 104. Each cell controller 104 is configured to control a corresponding one 202 of the converter cells 202 in the phase leg based on a corresponding cell control signal generated from the control signal. The control causes the magnitude of the circulating current to be a predetermined magnitude. The unit control signals are generated separately based on the control signals, and the unit control signals are generated separately for the converter units. In some embodiments, the unit controller 104 generates a PWM signal based on the unit control signal and controls the inverter unit via the PWM signal such that the magnitude of the circulating current is controlled to a predefined magnitude. In some embodiments, the converter cell is controlled by a cell control signal such that the amplitude of the third harmonic circulating current is controlled at an amplitude of 0.167 pu.
In some embodiments, the unit controller 104 is further configured to receive a DC voltage value indicative of a DC voltage across a DC capacitor in the converter unit. The unit controller 104 compares the DC voltage value with a nominal value to generate a compensation factor, and controls the converter unit based on the generated compensation factor and the unit control signal. In this way, the unit controller 104 may compensate the unit control signal based on the DC voltage value and control the converter unit based on the compensation control signal. In this way, the voltage ripple of the DC capacitor in each converter cell is further reduced, thereby further extending the operating life of the DC capacitor.
Fig. 2 shows a circuit diagram of a delta-connected cascaded multilevel converter 110. The converter topology of a delta-connected cascaded multilevel converter for MV drive is shown in fig. 2. Inverter 110 includes three phase arms connected between terminals a and B, between terminals B and C, and between terminals C and a, respectively. The converter 110 includes a plurality of converter cells 202 in each phase leg. A plurality of converter cells 202 are cascaded in each phase leg. The converter 110 may also include a limb inductor 204 in each phase limb. As shown in fig. 2, a circulating current flows in the phase leg of the inverter 110. Such circulating currents are typically caused by a variety of reasons including Transformer Symmetry Tolerance (TST), individual cell DC voltage ripple, and the like. In some embodiments, the circulating current flows in a clockwise direction as shown in fig. 2. In other embodiments, the circulating current may flow in a counter-clockwise direction.
Fig. 3 shows a circuit diagram of a converter cell 202 of the delta-connected cascaded multilevel converter 110. As shown in fig. 3, the converter unit 202 includes an AC source 302, a rectifying circuit 304, a capacitor 306, and a bridge circuit 308. The rectifying circuit 304 includes a diode to rectify the AC current supplied from the AC source 302 to generate a DC current. The capacitor 306 outputs a DC voltage to the bridge circuit 308. The bridge circuit 308 outputs AC current converted from DC voltage. In some embodiments, bridge circuit 308 may comprise a full bridge circuit as shown in FIG. 3. In other embodiments, bridge circuit 308 may comprise a half-bridge circuit. Bridge circuit 308 includes transistors that receive PWM signals for outputting a desired AC current or voltage.
In some embodiments, the cell controller 104 generates a PWM signal based on the cell control signal and outputs the PWM signal to the transistor to control switching of the transistor. Thus, the cell controller 104 controls the output current of the transistor based on the cell control signal. The circulating currents are combined into an output current, and the combined current flows in the phase leg. In addition, the inverter controller 102 generates a control signal based on the circulating current in the output current. Based on the control signals, unit control signals are generated for the inverter units 202, respectively. In this way, the inverter controller 102 generates control signals for controlling the inverter units 202 through the respective unit controllers 104 such that the circulating current in the output current is controlled to a desired magnitude. That is, the inverter controller controls the circulating current in a closed-loop manner such that the magnitude of the circulating current is maintained at a desired value. In this way, a circulating current having a desired magnitude is injected into the phase legs of the converter 110.
Fig. 4 shows a graph of the third order harmonic circulating current of the delta-connected cascaded multilevel converter 110. In the waveforms shown in fig. 4, sinwt represents the rated output current of the transistors in the converter unit 202, and Iz sin3wt represents the third order harmonic circulating current flowing in the converter 110, where I Z Representing the magnitude of the third harmonic circulating current injected into the converter 110. In addition, i L (=sinwt+iz×sin3wt) represents the phase current flowing through the three-phase arm in the inverter 110.
As shown in FIG. 4, as Iz increases from 0pu to 1pu, i L The peak of (c) decreases first and then increases. According to the formula, when iz=0.167 pu, the peak value i of the phase current is calculated L_peak A minimum value of 0.866pu can be reached. Furthermore, 1/0.866≡1.155 means that injecting a third order harmonic circulating current with a magnitude of 0.167pu (i.e. iz=0.167 pu) can help the converter 110 to obtain about 15.5% additional power. In this way, the power capacity of the converter 110 is increased even while the original power component of the converter 110 is kept unchanged. Furthermore, due to the peak value i of the phase current L_peak The voltage ripple of the DC capacitor in each converter cell is reduced.
Fig. 5 illustrates a block diagram of a system 500 for controlling a delta-connected cascaded multi-level converter 110 in accordance with an embodiment of the present disclosure. In some embodiments, the system 500 includes a first controller 502, a second controller 504, and the apparatus 100 described with reference to fig. 1. In some embodiments, system 500 includes a first controller 502, a second controller 504, a converter controller 102, and a unit controller 104.
In some embodiments, the first controller 502 is configured to generate a phase voltage reference signal associated with a load electrically coupled to the converter 110. In some embodiments, the phase voltage reference signal is associated with a motor model flux and torque, and the first controller 502 generates the phase voltage reference signal based on the calculated motor model flux and torque and the associated reference signal. A phase voltage reference signal is generated for controlling the converter unit 202 to provide output power associated with the load.
In some embodiments, the second controller 504 is configured to generate a plurality of cell control signals for the plurality of converter cells 202 based on the harmonic voltage signals. The phase voltage reference signal generated by the first controller 502 is combined with the harmonic voltage signal generated by the converter controller 102 to generate a control signal. The second controller 504 receives the control signals and generates a plurality of unit control signals based on the control signals. In some embodiments, an adder is provided external to the converter controller 102 and is configured to combine the phase voltage reference signal with the harmonic voltage signal. In other embodiments, an adder is provided in the converter controller 102 to combine the phase voltage reference signal with the harmonic voltage signal.
In some embodiments, the second controller 504 generates the corresponding cell control signals based on the converter cells 202 included in the converter 110. In some embodiments, the second controller 504 provides an interface between the converter controller 102 and the unit controller 104. The second controller 504 distributes respective unit control signals applicable to control the converter unit 202 to the unit controllers 104.
In some embodiments, a plurality of cell controllers 104 are provided that respectively correspond to a plurality of converter cells 202 included in the converter 110. Each of the unit controllers 104 receives a corresponding unit control signal from the second controller 504 to generate a PWM signal based on the unit control signal. Further, each of the cell controllers 104 transmits a PWM signal to the corresponding converter cell 202, and controls the transistors in the converter cell 202 to switch to generate an output current. In this way, the converter unit 202 of the converter 110 is controlled based on the control signal generated by combining the harmonic voltage signals such that the circulating current has a predefined amplitude. In this way, the phase current obtained by combining the circulating current and the output current is controlled to have the magnitude of the predetermined peak value sense.
Fig. 6 shows a block diagram of an apparatus 100 for controlling the circulating current of a delta-connected cascaded multi-level converter 110 in accordance with an embodiment of the present disclosure.
The first controller 502 generates a phase voltage reference signal V abc_ref And the converter controller 102 generates a harmonic voltage signal U abc_ref . In some embodiments, adder 602 is disposed external to converter controller 102 and provides phase voltage reference signal V abc_ref And harmonic voltage signal U abc_ref The combination is performed to generate the control signal as shown in fig. 6. In other embodiments, adder 602 is included in converter controller 102.
The second controller 504 receives the control signals from the adder 602 to generate corresponding unit control signals for the converter unit 202.
The cell controllers 104 each receive a cell control signal from the second controller 504 to generate PWM signals for controlling the corresponding bridge circuits 308 in the converter cells 202. In some embodiments, the unit controller 104 is further configured to receive a DC voltage value Udc indicative of the DC voltage across the capacitor 306 in the converter unit 202. The unit controller 104 is configured to compare the DC voltage value Udc with a nominal value, generating a compensation factor. Further, the unit controller 104 is configured to control the converter unit 202 based on the generated compensation factor and the unit control signal.
In some embodiments, the unit controller 104 is configured to generate the compensation factor by dividing the DC voltage value by the nominal value. The unit controller 104 is configured to determine a compensation control signal by dividing the level of the unit control signal by a compensation factor, and to control the converter unit 202 based on the compensation control signal. The compensated PWM signal is provided as a compensation control signal to the bridge circuit 308 to control the output current. In this way, the voltage ripple of the capacitor 306 in each converter cell 202 is further reduced, thereby further extending the operating life of the DC capacitor.
Fig. 7 shows a block diagram of the converter controller 102 according to an embodiment of the disclosure. As shown in fig. 7, the converter controller 102 may include a calculation module 702 and a reference voltage generation module 704.
In some embodiments, the calculation module 702 receives a current signal I indicative of a phase current flowing through the arm inductor arm_a 、I arm_b And I arm_c . The current signal may be measured by a current sensor. As shown in fig. 7, the calculation module 702 may include a Phase Locked Loop (PLL) unit to obtain a fundamental phase angle wt of the output current, and may then generate a phase angle 3wt of the third order harmonic circulating current. The calculation module 702 may further include an averaging unit for obtaining the amplitude of the third harmonic circulating current. The calculation module 702 may also include a transformation unit to obtain the DC component and the AC component of the third harmonic circulating current. The calculation module 702 may also include a Low Pass Filter (LPF) to obtain a third harmonic circulating current I 3d 、I 3q Is included in the DC component of (a). I 3d And I 3q Is Iz in DQ vector. I 3d_ref And I 3q_ref Is the reference DC component of the reference current for closed loop control of the third harmonic circulating current in the DQ vector.
In some embodiments, the reference voltage generation module 704 will I 3d And I 3d_ref Compare to generate a first DC difference, and compare I 3q And I 3q_ref A comparison is made to generate a second DC difference. In order to inject a third harmonic circulating current into the phase arm for power expansion of the converter 110, the phase angles of the third harmonic circulating current and the fundamental current in the phase arm should be equal when wt=2kpi (k=0, 1, 2 … …). To achieve thisOne point, I 3d_ref Should be set to the desired amplitude Iz, and I 3q_ref =0pu. In some embodiments, iz=0.167 pu. The reference voltage generation module 704 includes a PI control unit and a conversion unit to generate the harmonic voltage signal U based on the first DC difference and the second DC difference abc_ref For controlling the third harmonic circulating current to have a predefined amplitude in a closed loop PI control manner.
It should be noted that the implementation of the inverter controller 102 shown in fig. 7 is merely one exemplary example, and the present disclosure is not limited thereto. In other embodiments, the converter controller 102 may control any order harmonic circulating current in a closed loop manner. In other embodiments, the inverter controller 102 may be implemented as any other type of closed loop PI control.
In other embodiments, the inverter controller 102 may be implemented in a closed loop PR control. In these embodiments, the converter controller 102 is configured to determine the first AC component and the second AC component of the harmonic current signal from the current signal. The inverter controller 102 compares the first AC component to a first reference AC component of the reference current signal, generates a first AC difference, and compares the second AC component to a second reference AC component of the reference current signal, generates a second AC difference. Further, the inverter controller 102 generates a harmonic voltage signal based on the first AC difference and the second AC difference.
According to some embodiments, injecting a circulating current may help to spread the power capacity of a delta-connected cascaded multi-level converter with little to no modification to the hardware system of the converter. Thus, the capital cost of the converter can be saved. For example, by using third order harmonic circulating current control for the converter, the rated power range of the converter can be further extended by about 15.5% with little or no modification to the hardware system of the converter. Thus, for voltage driven applications, power range expansion is achieved with minimal material cost of the converter.
Furthermore, the voltage ripple of the DC capacitor in each converter cell is reduced, which may help to extend the operational lifetime of the DC capacitor. DC capacitors are a major component in delta-connected cascaded multilevel converters. This lifetime extension of the DC capacitor is very helpful for extending the lifetime of the converter and reducing the maintenance costs of such converters. Therefore, by limiting the voltage fluctuation of the DC capacitor, the lifetime of the DC capacitor in each converter cell of the converter is prolonged and the maintenance cost is reduced.
And establishing a simulation model of the triangle connection cascade multilevel converter in MATLAB. Table 1 lists the parameters of the simulation model.
TABLE 1
Table 2 shows simulation results. I L_peak Indicating the peak value of the current flowing through the arm inductor, I Z_peak Representing the peak value of the third-order harmonic circulating current, and P loss_arm Representing the power loss when the arm current flows through a 1Ω resistor, i.e., (≡i) L 2 dt)/T。
TABLE 2
It can be seen that the peak value of the current through the arm inductor decreases from 1.13pu to 0.89pu for the same motor load with the help of the inverter control. Thus, the fundamental current of the delta-connected converter can be further increased from 0.89pu to 1.0pu, which means that the rated power of the converter is increased by about +15%.
Simulation results are shown in table 3 for voltage fluctuations of the DC capacitor in each converter cell. It can be seen that the voltage ripple decreases significantly as the current amplitude of the third harmonic circulating current reference Iz _ ref increases. Thus, more circulating current injection may help to further reduce DC voltage ripple.
TABLE 3 Table 3
Fig. 8 shows a graph of simulation results with and without a converter controller according to an embodiment of the disclosure. And establishing a simulation model of the triangle connection cascade multilevel converter in MATLAB. IL denotes the phase current through the arm inductor and Iz denotes the circulating current. A similar conclusion can also be drawn from fig. 8, wherein the peak value of the phase current IL in the waveform shown in part (a) of fig. 8 is much larger than the peak value of the phase current IL in the waveform shown in part (b) of fig. 8.
Fig. 9 shows a graph of simulation results of closed loop control feedback of a converter controller in accordance with an embodiment of the disclosure. Fig. 9 shows that the feedback of the closed loop control may follow the reference signal.
According to embodiments of the present disclosure, circulating current control of the converter facilitates extending the rated power range of the converter by approximately 15.5% with little or no modification to the hardware system of the converter. Furthermore, the voltage ripple of the DC capacitor in each converter cell is reduced, which may help to extend the operational lifetime of the DC capacitor. This lifetime extension of the DC capacitor is very helpful for extending the lifetime of the converter and reducing the maintenance costs of such converters. In this way, a power range expansion is obtained with minimal material costs of the converter, and the lifetime of the DC capacitors in each converter cell of the converter is prolonged, reducing maintenance costs.
Fig. 10 illustrates a flowchart 1000 of a method for controlling the circulating current of a delta-connected cascaded multilevel converter according to an embodiment of the disclosure.
At block 1002, the method includes receiving a current signal indicative of a phase current flowing through a respective phase leg of the converter.
At block 1004, the method includes determining a harmonic current signal from the current signal that is indicative of a circulating current of the converter. In some embodiments, the first DC component and the second DC component of the harmonic current signal are determined from the current signal. In other embodiments, the first AC component and the second AC component of the harmonic current signal are determined from the current signal.
At block 1006, the method includes generating a harmonic voltage signal based on the determined harmonic current signal and a reference current signal. The harmonic voltage signal causes the amplitude of the circulating current flowing through the phase leg of the converter to be a predetermined amplitude. In some embodiments, the amplitude of the third harmonic circulating current is controlled to be 0.167 times the rated current amplitude of the converter.
In some embodiments, the harmonic voltage signal is generated based on a comparison of the harmonic current signal and a reference current signal. In some embodiments, the first DC component is compared to a first reference DC component of the reference current signal, generating a first DC difference, and the second DC component is compared to a second reference DC component of the reference current signal, generating a second DC difference. In some embodiments, the first DC component is compared to 0.167 times the converter rated current amplitude and the second DC component is compared to zero. Further, a harmonic voltage signal is generated based on the first DC difference and the second DC difference.
In other embodiments, the first AC component is compared to a first reference AC component of the reference current signal to generate a first AC difference, and the second AC component is compared to a second reference AC component of the reference current signal to generate a second AC difference. Further, a harmonic voltage signal is generated based on the first AC difference and the second AC difference.
In some embodiments, the method may further include receiving a phase voltage reference signal associated with a load electrically coupled to the converter. The method may further include generating a control signal by combining the harmonic voltage signal with the phase voltage reference signal. The control signal is used to control the inverter such that the peak amplitude of the phase current is a first amplitude. The first amplitude is associated with a second amplitude of the circulating current in the phase current.
In some embodiments, the method may further include controlling one of the plurality of inverter units of the phase leg based on a unit control signal generated from the control signal. The control causes the magnitude of the circulating current to be a predetermined magnitude. In some embodiments, the method further comprises receiving a DC voltage value indicative of a DC voltage across a capacitor of one of the plurality of converter cells. The DC voltage value is compared to a nominal value to generate a compensation factor. In some embodiments, the compensation factor is generated by dividing the DC voltage value by the nominal value. Further, one of the plurality of converter units is controlled based on the generated compensation factor and the unit control signal. In some embodiments, one of the plurality of converter units is controlled based on the compensation control signal.
According to another aspect of the present disclosure, a computer-readable medium is provided. The computer-readable medium includes instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method as described above.
While several details are included in the above discussion, these should not be construed as limitations on the scope of the subject matter described herein, but rather as descriptions of features specific to particular embodiments. The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (20)
1. An apparatus (100) for controlling a delta-connected cascaded multilevel converter (110), comprising:
a converter controller (102), the converter controller (102) being configured to:
receiving a current signal indicative of a phase current flowing through a respective phase leg of the converter (110);
Determining from the current signal a harmonic current signal indicative of a circulating current of the converter (110); and is also provided with
Generating a harmonic voltage signal based on the determined harmonic current signal and a reference current signal such that the magnitude of a circulating current flowing through a phase leg of the converter (110) is a predetermined magnitude,
wherein the converter controller (102) is configured to generate the harmonic voltage signal based on a comparison of the harmonic current signal and the reference current signal; and is also provided with
Wherein the converter controller (102) is configured to:
determining a first DC component of the harmonic current signal from the current signal;
comparing the first DC component with a first reference DC component of the reference current signal to generate a first DC difference;
determining a second DC component of the harmonic current signal from the current signal;
comparing the second DC component with a second reference DC component of the reference current signal to generate a second DC difference; and is also provided with
The harmonic voltage signal is generated based on the first DC difference and the second DC difference.
2. The apparatus (100) of claim 1, wherein the converter controller (102) is configured to:
Determining the harmonic current signal from the current signal, the harmonic current signal being indicative of a third order harmonic circulating current of the converter (110); and is also provided with
The harmonic voltage signal is generated such that the amplitude of the third harmonic circulating current is 0.167 times the amplitude of the rated current of the converter (110).
3. The apparatus (100) of claim 1, wherein the converter controller (102) is further configured to:
receiving a phase voltage reference signal associated with a load of the converter (110), the load being electrically coupled to the converter (110); and is also provided with
Generating a control signal for controlling the converter (110) by combining the harmonic voltage signal with the phase voltage reference signal such that the peak amplitude of the phase current is a first amplitude,
wherein the first amplitude is associated with a second amplitude of the circulating current in the phase current.
4. The apparatus (100) of claim 1, wherein a first reference DC component of the reference current is set to 0.167 times the magnitude of the rated current of the converter (110) and a second reference DC component of the reference current is set to zero.
5. The apparatus (100) of claim 1, wherein the converter controller (102) is configured to:
Determining a first AC component of the harmonic current signal from the current signal;
comparing the first AC component with a first reference AC component of the reference current signal to generate a first AC difference;
determining a second AC component of the harmonic current signal from the current signal;
comparing the second AC component with a second reference AC component of the reference current signal to generate a second AC difference; and is also provided with
The harmonic voltage signal is generated based on the first AC difference and the second AC difference.
6. The apparatus (100) of claim 3, further comprising:
-a cell controller (104), the cell controller (104) being configured to control one of a plurality of converter cells (202) in the phase leg such that the magnitude of the circulating current is the predetermined magnitude, based on a cell control signal generated from the control signal.
7. The apparatus (100) of claim 6, wherein the unit controller (104) is further configured to:
receiving a DC voltage value indicative of a DC voltage across a capacitor (306) in one of the plurality of converter cells (202);
comparing the DC voltage value with a nominal value to generate a compensation factor; and is also provided with
-controlling one of the plurality of converter units (202) based on the generated compensation factor and the unit control signal.
8. The apparatus (100) of claim 7, wherein the unit controller (104) is configured to generate the compensation factor by dividing the DC voltage value by the nominal value.
9. The apparatus (100) of claim 8, wherein the unit controller (104) is configured to:
determining a compensation control signal by dividing a level of the unit control signal by the compensation factor; and is also provided with
-controlling one of the plurality of converter units (202) based on the compensation control signal.
10. A method for controlling a delta-connected cascaded multilevel converter (110), comprising:
receiving a current signal indicative of a phase current flowing through a respective phase leg of the converter (110);
determining from the current signal a harmonic current signal indicative of the circulating current of the converter (110); and
generating a harmonic voltage signal based on the determined harmonic current signal and a reference current signal such that the magnitude of a circulating current flowing through a phase leg of the converter (110) is a predetermined magnitude,
Wherein generating the harmonic voltage signal includes generating the harmonic voltage signal based on a comparison of the harmonic current signal and the reference current signal; and is also provided with
Wherein generating the harmonic voltage signal based on the comparison comprises:
determining a first DC component of the harmonic current signal from the current signal;
comparing the first DC component with a first reference DC component of the reference current signal to generate a first DC difference;
determining a second DC component of the harmonic current signal from the current signal;
comparing the second DC component with a second reference DC component of the reference current signal to generate a second DC difference; and
the harmonic voltage signal is generated based on the first DC difference and the second DC difference.
11. The method of claim 10, wherein determining the harmonic current signal indicative of the circulating current comprises determining the harmonic current signal indicative of a third order harmonic circulating current, and
wherein generating the harmonic voltage signal such that the magnitude of the circulating current is the predetermined magnitude comprises generating the harmonic voltage signal such that the magnitude of the third harmonic circulating current is 0.167 times the magnitude of the rated current of the converter (110).
12. The method of claim 10, further comprising:
receiving a phase voltage reference signal associated with a load of the converter (110), the load being electrically coupled to the converter (110); and
generating a control signal for controlling the converter (110) by combining the harmonic voltage signal with the phase voltage reference signal such that the peak amplitude of the phase current is a first amplitude,
wherein the first amplitude is associated with a second amplitude of circulating current in the phase current.
13. The method of claim 10, wherein comparing the first DC component to the first reference DC component includes comparing the first DC component to 0.167 times a rated current amplitude of the converter (110), and
wherein comparing the second DC component to the second reference DC component comprises comparing the second DC component to zero.
14. The method of claim 10, wherein generating the harmonic voltage signal based on the comparison comprises:
determining a first AC component of the harmonic current signal from the current signal;
comparing the first AC component with a first reference AC component of the reference current signal to generate a first AC difference;
Determining a second AC component of the harmonic current signal from the current signal;
comparing the second AC component with a second reference AC component of the reference current signal to generate a second AC difference; and
the harmonic voltage signal is generated based on the first AC difference and the second AC difference.
15. The method of claim 12, further comprising:
one of a plurality of inverter units (202) in the phase arm is controlled based on a unit control signal generated from the control signal such that the magnitude of the circulating current is the predetermined magnitude.
16. The method of claim 15, further comprising:
receiving a DC voltage value indicative of a DC voltage across a capacitor (306) in one of the plurality of converter cells (202);
comparing the DC voltage value with a nominal value to generate a compensation factor; and
-controlling one of the plurality of converter units (202) based on the generated compensation factor and the unit control signal.
17. The method of claim 16, wherein generating the compensation factor comprises generating the compensation factor by dividing the DC voltage value by the nominal value.
18. The method of claim 17, wherein controlling one of the plurality of converter units (202) comprises:
determining a compensation control signal by dividing a level of the unit control signal by the compensation factor; and
-controlling one of the plurality of converter units (202) based on the compensation control signal.
19. A system (500) for controlling a delta-connected cascaded multilevel converter (110), comprising:
the device (100) according to any one of claims 1-9;
-a first controller (502), the first controller (502) being configured to generate a phase voltage reference signal based on a load electrically coupled to the converter (110); and
-a second controller (504), the second controller (504) being configured to generate a plurality of cell control signals for a plurality of converter cells (202) based on the harmonic voltage signal.
20. A computer-readable medium having instructions stored thereon, which when executed on at least one processor, cause the at least one processor to perform the method of any of claims 10-18.
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| PCT/CN2020/077183 WO2021168791A1 (en) | 2020-02-28 | 2020-02-28 | Apparatus and method for controlling delta-connected cascaded multilevel converter |
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| CN102044879A (en) * | 2010-12-31 | 2011-05-04 | 中电普瑞科技有限公司 | Movable type static synchronous compensator (STATCOM) with modularization structure |
| CN102545235A (en) * | 2010-12-31 | 2012-07-04 | 清华大学 | Triangular connection type comprehensive compensation system integrated with cascaded active filter and reactive compensator |
| CN102742142A (en) * | 2010-02-25 | 2012-10-17 | 株式会社日立制作所 | Electric power conversion device |
| CN102957151A (en) * | 2011-08-22 | 2013-03-06 | 台达电子企业管理（上海）有限公司 | Power compensation device and power compensation method for renewable energy source system |
| CN103999339A (en) * | 2011-12-15 | 2014-08-20 | 西门子公司 | Converter in delta configuration |
| WO2019081503A1 (en) * | 2017-10-27 | 2019-05-02 | Abb Schweiz Ag | Control of delta-connected converter |
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| US9379632B2 (en) * | 2011-01-18 | 2016-06-28 | Tokyo Institute Of Technology | Power converter and method for controlling same |
| CN108306320A (en) * | 2017-12-11 | 2018-07-20 | 广州智光电气股份有限公司 | A kind of energy accumulation current converter and energy storage converter system |
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- 2020-02-28 WO PCT/CN2020/077183 patent/WO2021168791A1/en unknown
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102742142A (en) * | 2010-02-25 | 2012-10-17 | 株式会社日立制作所 | Electric power conversion device |
| CN102044879A (en) * | 2010-12-31 | 2011-05-04 | 中电普瑞科技有限公司 | Movable type static synchronous compensator (STATCOM) with modularization structure |
| CN102545235A (en) * | 2010-12-31 | 2012-07-04 | 清华大学 | Triangular connection type comprehensive compensation system integrated with cascaded active filter and reactive compensator |
| CN102957151A (en) * | 2011-08-22 | 2013-03-06 | 台达电子企业管理（上海）有限公司 | Power compensation device and power compensation method for renewable energy source system |
| CN103999339A (en) * | 2011-12-15 | 2014-08-20 | 西门子公司 | Converter in delta configuration |
| WO2019081503A1 (en) * | 2017-10-27 | 2019-05-02 | Abb Schweiz Ag | Control of delta-connected converter |
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| EP4111580A1 (en) | 2023-01-04 |
| EP4111580A4 (en) | 2023-11-29 |
| US20220407407A1 (en) | 2022-12-22 |
| WO2021168791A1 (en) | 2021-09-02 |
| CN114402516A (en) | 2022-04-26 |
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